1. Field of the Invention
The present invention relates to a method of manufacturing an organic electroluminescent display device, an organic electroluminescent display device, and a display device equipped with an organic electroluminescent display device, the organic electroluminescent display device making a display through the light-emitting state of a plurality of organic luminescent layers.
2. Description of the Related Art
Current display devices can be classified into CRTs (Cathode Ray Tubes) and flat display panels composed of various types of elements. Flat display panels are light-weight and have a better luminous efficiency than CRTs, and have been developed over the years for use as monitor screens for computers, televisions and the like. Recently, research is focusing on active matrix driven organic EL (Electroluminescence) displays.
The organic EL display is of a configuration that sandwiches a thin film including a fluorescent inorganic and organic compound between a cathode and an anode, and the configuration has an array of elements that are induced to emit light using the radiation of light (fluorescence, phosphorescence) produced when excitons decay that have been generated by recombination of electrons and holes injected in the thin film. Such active matrix driven organic EL displays are getting a lot of attention as they feature a thin structure and high resolution.
FIG. 10 is a sectional view showing an example of a configuration of an organic EL panel 101a included in a conventional organic EL display.
The organic EL panel 101a has a configuration wherein a light-emitting element 114 and a desiccant 109 are sealed through a transparent glass 111 and a sealing glass 111a. In this organic EL panel 101a, the space sealed by the glass 111 and the sealing glass 111a is desiccated by the desiccant 109, and light Lp emitted by a light-emitting element 114 crosses the glass 111 and is emitted to the outside.
With surface emitting elements such as the organic panel 101a, a problem is encountered in that light is lost and thus the light output efficiency is poor, as the light Lp from the pixel including the light-emitting element 114 is diffused in all directions and light Lu, having an angle exceeding the critical angle with regard to the surface of the glass 111, cannot be emitted to the outside of the glass 111 due to a total reflection phenomenon.
Conventionally, to solve such problems, organic EL light-emitting devices of a configuration such as the one shown in Japanese unexamined patent application publication 10-172756 have been known.
Such a conventional organic EL light-emitting device uses a configuration, wherein a microlens 2 is located inside a light transmissive base board 1 as shown in FIG. 1 appended to the patent application publication, a microlens 22 is located inside a light transmissive base board 21 as shown in FIG. 2, microlenses 32 and 33 are located inside a light transmissive base board 31 as shown in FIG. 3. However, with such a conventional configuration, it is difficult and thus costly to place the microlens 2 inside the light transmissive base board 1.
Further, in FIG. 4 of unexamined patent application publication H10-172756, a configuration is used wherein a microlens 42 is provided inside a backing layer 43 that is formed on a light transmissive base board 41.
An organic EL light-emitting device 40 has a configuration wherein the microlens inside the backing layer 43 has a convex curved surface formed on the side of the light transmissive base board 41 rather than on the side of the lower electrode 44a. 
In the organic EL light-emitting device 40 of such a configuration, when comparing it to an organic EL light-emitting device 10 shown in FIG. 1 and others, the difficulty with manufacturing is seemingly resolved because the microlens 42 is not formed inside the light transmissive base board 41 anymore.
However, in such an organic EL light-emitting device 40, as the microlens 42 inside the backing layer 43 has a convex curved surface formed on the side of the translucent substrate 41, a problem exists in that, when the light from a light-emitting layer 44b that is provided between an opposed electrode 44c and the lower electrode 44a is refracted, the margin of the critical angle is small, at which the light ends up being reflected inside the microlens 42 instead of being transmitted through the light transmissive base board 41.
Further, in unexamined patent application publication H10-172756, no concrete manufacturing procedure is disclosed regarding the organic EL light-emitting device 40 shown in FIG. 4. Further, for the active matrix driven organic EL light-emitting device 40, the manufacturing seems problematical, as the substrate process becomes a high temperature process of about 500 degrees that requires the microlens 42 itself to be able to withstand such high temperatures.
Here, the present invention is intended to solve the above-mentioned issue by providing a method of manufacturing an organic electroluminescent display device, an organic electroluminescent display device, and a display device equipped with an organic electroluminescent display device that enable a microlens to be formed without affecting an organic luminescent layer during the manufacturing process, and to easily manufacture an organic electroluminescent display device with increased light output efficiency.